<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Gradual Change</title>
    <style>
        .background-gradient {
            background: rgb(44, 136, 207);
            position: relative;
            width: 500px;
            height: 200px;
        }
        .background-gradient .mask {
            background-image: linear-gradient(to right, rgb(44, 136, 207), transparent), url("https://pic1.zhimg.com/50/v2-6c5aa2304a93b7fbaf903e3560543d7b_hd.jpg");
            background-position:center;
            background-blend-mode:normal;
            position: absolute;
            height: 100%;
            width: 180px;
            right: 0;
            }
    </style>
</head>
<body>
<!-- 有色到透明的背景渐变 -->
<div class="background-gradient">
    <div class="mask"></div>
</div>
</body>
</html>
